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Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -339,6 +339,25 @@
return (false);
}
+/*
+ * We can cluster only if the page is not clean, busy, or held, and the page is
+ * in the laundry queue.
+ */
+static bool
+vm_pageout_flushable(vm_page_t m)
+{
+ if (vm_page_tryxbusy(m) == 0)
+ return (false);
+ if (!vm_page_wired(m)) {
+ vm_page_test_dirty(m);
+ if (m->dirty != 0 && vm_page_in_laundry(m) &&
+ vm_page_try_remove_write(m))
+ return (true);
+ }
+ vm_page_xunbusy(m);
+ return (false);
+}
+
/*
* Scan for pages at adjacent offsets within the given page's object that are
* eligible for laundering, form a cluster of these pages and the given page,
@@ -348,7 +367,7 @@
vm_pageout_cluster(vm_page_t m)
{
vm_object_t object;
- vm_page_t mc[2 * vm_pageout_page_count - 1], p, pb, ps;
+ vm_page_t mc[2 * vm_pageout_page_count - 1];
vm_pindex_t pindex;
int ib, is, page_base, pageout_count;
@@ -360,14 +379,11 @@
pageout_count = 1;
page_base = nitems(mc) / 2;
- mc[page_base] = pb = ps = m;
+ mc[page_base] = m;
ib = 1;
is = 1;
/*
- * We can cluster only if the page is not clean, busy, or held, and
- * the page is in the laundry queue.
- *
* During heavy mmap/modification loads the pageout
* daemon can really fragment the underlying file
* due to flushing pages out of order and not trying to
@@ -377,33 +393,19 @@
* forward scan if room remains.
*/
more:
+ m = mc[page_base];
while (ib != 0 && pageout_count < vm_pageout_page_count) {
if (ib > pindex) {
+ /* Don't walk backward from pindex 0. */
ib = 0;
break;
}
- if ((p = vm_page_prev(pb)) == NULL ||
- vm_page_tryxbusy(p) == 0) {
- ib = 0;
- break;
- }
- if (vm_page_wired(p)) {
+ m = vm_page_prev(m);
+ if (m == NULL || !vm_pageout_flushable(m)) {
ib = 0;
- vm_page_xunbusy(p);
break;
}
- vm_page_test_dirty(p);
- if (p->dirty == 0) {
- ib = 0;
- vm_page_xunbusy(p);
- break;
- }
- if (!vm_page_in_laundry(p) || !vm_page_try_remove_write(p)) {
- vm_page_xunbusy(p);
- ib = 0;
- break;
- }
- mc[--page_base] = pb = p;
+ mc[--page_base] = m;
++pageout_count;
++ib;
@@ -414,25 +416,13 @@
if ((pindex - (ib - 1)) % vm_pageout_page_count == 0)
break;
}
+ m = mc[page_base + pageout_count - 1];
while (pageout_count < vm_pageout_page_count &&
pindex + is < object->size) {
- if ((p = vm_page_next(ps)) == NULL ||
- vm_page_tryxbusy(p) == 0)
+ m = vm_page_next(m);
+ if (m == NULL || !vm_pageout_flushable(m))
break;
- if (vm_page_wired(p)) {
- vm_page_xunbusy(p);
- break;
- }
- vm_page_test_dirty(p);
- if (p->dirty == 0) {
- vm_page_xunbusy(p);
- break;
- }
- if (!vm_page_in_laundry(p) || !vm_page_try_remove_write(p)) {
- vm_page_xunbusy(p);
- break;
- }
- mc[page_base + pageout_count] = ps = p;
+ mc[page_base + pageout_count] = m;
++pageout_count;
++is;
}

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